A landline is a telephone that transmits signals converted from audio data through physical media, such as wire or fibre optic cable, rather than through wireless transmission as is the case with mobile phones. The term landline is also sometimes used to refer to a dedicated line, which is a permanent connection between two locations. However, in recent years, the term is mostly used to differentiate fixed-line home phones from mobiles.
There are two basic types of landlines. A corded landline is one that connects to the provider's cabling through a wall jack. The phone base and the receiver (or handset) are connected by a cord. In a cordless landline, the phone base connects to the cabling through a jack but the handset is connected wirelessly. The cordless phone's range is short, basically within the premises. Cordless landlines must also be plugged into the building's electrical system, which means that -- unlike corded landlines -- they don't function in power outages.
An ongoing trend towards fixed-mobile substitution (FMS), in which users cancel landline services and rely solely upon cellular phone service, has resulted in a sharp reduction in the numbers of landline subscribers. In 2012, for example, a USTelecom report revealed that 39% of all households in the United States used mobile phones exclusively. The act of canceling a landline for mobile service is also sometimes referred to as wireless substitution.
Cord cutting, a related telecommunications trend, is the act of canceling traditional TV services in favor of other options or canceling landline service in favor of either cellular or VoIP (voice over Internet Protocol) services.